1. Field of the Invention
The invention relates in general to a method and apparatus for dissolving crystals that form as a result of an unwanted side reaction in conjunction with oxidation-reduction chemical reactions, and more particularly to a method and apparatus of minimizing buildup of chemical deposits on battery plates and terminals by applying a low frequency square wave across the terminals.
2. Description of Related Art
Oxidation-reduction is a very common and an important type of chemical reaction. Oxidation-reduction reaction includes by definition any chemical reaction in which electrons are transferred. Oxidation-reduction reactions have many far reaching and useful applications, for example combustion, photosynthesis, metabolism, bleaching agents, electrochemistry, batteries, etc. In many instances however, oxidation-reduction reaction also produce a buildup of undesirable chemical deposits in the form of crystals, as in the case of a lead acid battery, where lead(II) sulfate (PbSO4) and lead(IV) sulfate (Pb(SO4)2 crystals are produced. A battery, such as used in the automotive field, is illustrative of one type of oxidation-reduction reaction. A characteristic of such electrolyte type batteries, particularly lead acid batteries, is that chemical compound deposits slowly build-up on plates to partially or entirely cover and displace the normal plate surfaces. Low current charging does not remove the deposits effectively. With the passage of time, the deposits crystallize and choke the battery by blocking electrolyte movement. During the process of charging a battery, the lead on one of the plates is converted to lead(IV) oxide (PbO2) and lead oxide on the other plate is reduced to lead. Under certain conditions, lead(II) sulfate (PbSO4) and lead(IV) sulfate (Pb(SO4)2) crystals are formed as an undesirable byproduct. The lead sulfate crystals coat the electrodes and prevent contact between the lead of the electrode and the sulfuric acid of the electrolyte, thus reducing the surface area available for the chemical reaction to take place. This, in turn, reduces the total power output capacity of the battery. Although some of the lead(II) sulfate is dissolved during charging, lead(II) and lead(IV) sulfate can build up to a point where the battery is considered totally unusable. Fast charging has been suggested, but fast charging frequently overheats the battery and warps the lead plates in a lead acid battery effectively shorting the plates so that the battery does not hold a charge.
Batteries using other electrolytes also suffer from maintenance and charging problems that need to be addressed. A nickel cadmium battery serves as an example. A nickel cadmium battery uses an oxidation-reduction chemical reaction to create the desired electrical current. One of the plates of a nickel cadmium battery uses a material called nickel sponge, a form of almost pure nickel in a very open structure, which gives it a large surface area. The large surface area is necessary to generate the maximum amount of current. As this battery is used, undesirable crystals form in the lattice of the nickel sponge and block the electrolyte from contacting the surface of the electrode. These undesirable crystals can build up to a point where the battery becomes unusable.
Oxidation-reduction is also referred to as redox. Redox chemical reaction involves the use of electron donor salts and electron hungry salts, usually in a resin matrix or bed with large surface areas. There are other redox processes that use electrolysis to aid the reaction. These would be classed as electrochemical. In these processes, complex, multiple step oxidation-reduction reactions take place such as in the leaching of gold and other precious metal ores, and when side reactions forming unwanted crystals take place, these crystals can be dissolved using my invention. Another example of an electrochemical redox process is the electrolysis of water to form hydrogen and oxygen. Fouling of the electrodes can occur by the build up of calcium carbonate.
It is therefore an object of my invention to prevent or minimize the buildup of undesirable and unwanted chemical deposits occurring from oxidation-reduction chemical reactions.
Others have recognized that for specific applications such as lead acid batteries a resonant excitation of the sulfate crystals in the battery may reduce crystal formations.
For example U.S. Pat. No. 5,891,590 of King discloses a system employing a signal generator coupled by a transformer to deliver an alternating current signal of selected frequency at the output of the transformer secondary winding. The signal is rectified to deliver a train of direct current pulses through an output circuit at a high frequency range of 10,000 to 52,000 hertz to cover the crystals to crack and soften and eventually dissolve in the battery solution. The system of King is used with lead acid batteries and, accordingly, is not adaptable to all oxidation reduction process. It also requires high and variable frequency on the range of 20 Khz to 32 Khz.
U.S. Pat. No. 6,078,166 of Taricco discloses a battery charger employing an external AC power source for recharging lead-acid batteries. Like King, it operates at frequencies above 10,000 hertz. Noise created by the resonant excitation is fed back to the modulator to create and or enhance the noise on the rail voltage to recharge the battery.
The present invention overcomes the disadvantages of such known arrangements which fail to effectively act on crystals having a resonant frequency below 10 Khz. Crystals formed as a result of oxidation-reduction are of varying sizes and these single frequency operation systems of the prior art only effects crystals resonant at that frequency.
The subject invention is more versatile in that it will work in all oxidation-reduction reactions, is more effective and advantageous because it will stimulate a larger variety of crystal sizes and will work with or without an external power sources. Another advantage of the present invention is that it is capable of delivering more power to stimulate a larger surface area of crystal formation known arrangement and is simpler and more economical, requiring only one integrated circuit and one transistor.
Another object of my invention is to provide an improved method for dissolving unwanted crystals that form as a by product of an oxidation-reduction chemical reaction.
Still another object of my invention is to provide a system for stimulating the natural frequency of the crystals of varying sizes formed as a result of an oxidation-reduction reaction, thus causing them to break up and dissolve.
Yet another object of my invention is to provide an improved system for stimulating unwanted crystals formed on battery plates causing them to break up and dissolve.